Re: CentOS 5 OpenLDAP Causes Server to Hang

[Dan White <dwhite@olp.net>]

On 02/13/12 15:50 -0600, Zachary Musselman wrote:
> Hello,
>
> I am running 2.6.18-274.17.1.el5 with openldap-2.3.43-12.el5_7.10.  Lately
> I've been seeing the following errors in /var/log/messages.  Once this
> error starts it appears to almost freeze the server.  I cannot connect via
> ssh and restarting services take minutes to restart if not restarting at
> all.  My only option is to reboot the server.  All is fine for a few days
> then it happens again.
>
> nss_ldap: could not search LDAP server - Server is unavailable
>
> This disconnects my samba shares and does not allow users to login to
> Windows anymore.
>
> Can anyone help me with this issue?

While the problem is happening, is slapd running? Do you have any limits
configured (man slapd.conf, and ldap.conf)? Do you have a large number of
connections to slapd (netstat)? Can you perform normal ldap operations
against the server using any of the client utilities (ldapsearch)?

If the problem points to slapd, try increasing your loglevel or running
slapd in debug mode to gather more information about what's happening.

You should upgrade your slapd version, and consider replacing nss_ldap with
nssov or nss-pam-ldapd, for a more robust handling of the case where slapd
is unavailable.

--
Dan White